package com.atguigu.chapter07;

import com.atguigu.chapter05.WaterSensor;
import org.apache.flink.api.common.eventtime.SerializableTimestampAssigner;
import org.apache.flink.api.common.eventtime.WatermarkStrategy;
import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.streaming.api.datastream.KeyedStream;
import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator;
import org.apache.flink.streaming.api.datastream.WindowedStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.functions.windowing.ProcessWindowFunction;
import org.apache.flink.streaming.api.windowing.assigners.TumblingEventTimeWindows;
import org.apache.flink.streaming.api.windowing.time.Time;
import org.apache.flink.streaming.api.windowing.windows.TimeWindow;
import org.apache.flink.util.Collector;

/**
 * TODO
 *
 * @author cjp
 * @version 1.0
 * @date 2021/3/6 9:12
 */
public class Flink09_Watermark {
    public static void main(String[] args) throws Exception {
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(1);

        // 以前的版本，默认是 处理时间，需要如下进行指定，才能使用事件时间
//        env.setStreamTimeCharacteristic(TimeCharacteristic.EventTime);

        SingleOutputStreamOperator<WaterSensor> sensorDS = env
                .socketTextStream("localhost", 9999)
                .map(new MapFunction<String, WaterSensor>() {
                    @Override
                    public WaterSensor map(String value) throws Exception {
                        // 切分
                        String[] line = value.split(",");
                        return new WaterSensor(line[0], Long.valueOf(line[1]), Integer.valueOf(line[2]));

                    }
                })
                .assignTimestampsAndWatermarks(
                        WatermarkStrategy
                                .<WaterSensor>forMonotonousTimestamps()      // 指定watermark的生成
                                .withTimestampAssigner(new SerializableTimestampAssigner<WaterSensor>() {
                                    @Override
                                    public long extractTimestamp(WaterSensor element, long recordTimestamp) {
                                        return element.getTs() * 1000L; // Flink时间戳单位都是 毫秒
                                    }
                                })

                );


        KeyedStream<WaterSensor, String> sensorKS = sensorDS.keyBy(sensor -> sensor.getId());

        // 分组之后开窗：
        WindowedStream<WaterSensor, String, TimeWindow> sensorWS = sensorKS
                .window(TumblingEventTimeWindows.of(Time.seconds(5)));


        sensorWS
                .process(new ProcessWindowFunction<WaterSensor, String, String, TimeWindow>() {
                    @Override
                    public void process(String key, Context context, Iterable<WaterSensor> elements, Collector<String> out) throws Exception {
                        out.collect("key=" + key + "\n" +
                                "数据条数:" + elements.spliterator().estimateSize() + "\n" +
                                "窗口是:[" + context.window().getStart() + "," + context.window().getEnd() + ")\n\n");
                    }
                })
                .print();


        env.execute();
    }
}

/*
    Watermark：
        1、衡量 事件时间的 进展
        2、触发 窗口（定时器） 的计算、关窗
        3、用来解决 乱序的 问题
        4、单调递增的（不会减少的）
        5、Flink认为，在它之前的数据都处理完了
        6、是一个特殊的时间戳， 生成之后会插入到流里面，随着流的流动而向下游传递

 */